Color conversion structure of micro-cavity enhanced quantum dots and preparation method of color conversion structure

Abstract

The invention relates to a microcavity enhanced quantum dot color conversion structure which comprises a substrate, a first reflecting layer, a blue light emitting layer, a quantum dot conversion layer and a second reflecting layer which are sequentially stacked, the blue light emitting layer emits blue light, and the quantum dot conversion layer is used for converting the blue light into red light or green light. A microcavity structure is formed between the first reflecting layer and the second reflecting layer, and stable blue light and red light resonance conditions are formed in the microcavity structure. Light is reflected in the microcavity structure to form blue light standing waves and red light standing waves, in the thickness direction, the blue light emitting layer is located at the wave crest position of the blue light standing waves, the quantum dot conversion layer is located at the wave crest overlapping position of the red light standing waves and the blue light standing waves, and the blue light excitation material and the red and green quantum dots are all located in the strongest light field area. The excitation efficiency of blue light is enhanced, and meanwhile, the luminous intensity of red light is improved; similarly, the luminous intensity of green light can be improved, and the color conversion efficiency of the quantum dot conversion layer is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of full-color display, and in particular to a color-changing structure of microcavity-enhanced quantum dots and a preparation method thereof. Background Art

[0002] In display technology, especially in the field of Mini-LED / Micro-LED full-color display, quantum dots are widely used as a highly efficient color conversion material. Quantum dots (QDs) have unique advantages in luminescence and display applications due to their high color purity, adjustable luminescent color, high fluorescence quantum yield, and excellent stability. Traditional quantum dot color conversion usually uses inkjet printing, photolithography, etc. However, these methods have limitations in the case of high-resolution display and small-size pixels, and it is difficult to meet the growing display performance requirements.

[0003] In order to improve the color conversion efficiency of quantum dots, researchers introduced a microcavity structure. The resonant characteristics of the microcavity can enhance the light field and strengthen the light field at a specific frequency, thereby improving the luminescence efficiency and color purity of the quantum dots. However, there are some problems in the existing microcavity enhancement structure. For example, the uneven distribution of the light field may lead to uneven excitation efficiency of quantum dots, which in turn affects the overall color conversion effect. In addition, quantum dots are prone to photodegradation under high-intensity light excitation, affecting the service life and performance stability of the display. This phenomenon is particularly evident under high-resolution and high-brightness display requirements. Therefore, how to optimize the intensity distribution of blue light in the microcavity structure and reasonably design the distribution of quantum dots and the position of the light field to improve the color conversion efficiency, uniformity and stability of the device has become a technical problem that needs to be solved. Summary of the invention

[0004] The present invention provides a color conversion structure of a microcavity-enhanced quantum dot and a preparation method thereof, and optimizes the intensity distribution of blue light in a microcavity and rationally designs the distribution of quantum dots and the light field position to improve the color conversion efficiency, uniformity and stability of the color conversion structure of the microcavity-enhanced quantum dot.

[0005] First aspect

[0006] The present invention discloses a color conversion structure of microcavity enhanced quantum dots, comprising a substrate, a first reflective layer, a blue light-emitting layer, a quantum dot conversion layer and a second reflective layer stacked in sequence, wherein the blue light-emitting layer emits blue light, and the quantum dot conversion layer can convert the blue light into red light or green light, a microcavity structure is formed between the first reflective layer and the second reflective layer, and the first reflective layer and the second reflective layer are configured to form a stable resonance condition of blue light and green light or a stable resonance condition of blue light and red light in the microcavity structure;

[0007] Among them, the light is reflected in the microcavity structure to form a blue light standing wave and a red light standing wave, and along the extension direction of the cavity length of the microcavity structure, the blue light-emitting layer is located at the crest of the blue light standing wave; the quantum dot conversion layer is located at the overlapping position of the crests of the red light standing wave and the blue light standing wave; or, the light is reflected in the microcavity structure to form a blue light standing wave and a green light standing wave, and along the extension direction of the cavity length of the microcavity structure, the blue light-emitting layer is located at the crest of the blue light standing wave; the quantum dot conversion layer is located at the overlapping position of the crests of the green light standing wave and the blue light standing wave.

[0008] In one embodiment, the microcavity enhanced quantum dot color conversion structure includes a first isolation layer, which is stacked between the quantum dot conversion layer and the blue light-emitting layer along the cavity length extension direction of the microcavity structure; and / or,

[0009] The microcavity enhanced quantum dot color conversion structure comprises a second isolation layer, and the second isolation layer is stacked and arranged between the quantum dot conversion layer and the second reflective layer along the cavity length extension direction of the microcavity structure.

[0010] In one embodiment, the first reflective layer and the second reflective layer are both DBR reflective layers.

[0011] In one embodiment, the blue light-emitting layer includes an n-electrode, n-GaN, a blue light multi-quantum well layer, p-GaN, and a p-electrode stacked in sequence, and the blue light multi-quantum well emits the blue light; the n-electrode stack is arranged on the first reflective layer, and the p-electrode stack is arranged on the quantum dot conversion layer.

[0012] In one embodiment, the quantum dot conversion layer includes red light quantum dots, which are used to convert blue light into red light, and the cavity length of the microcavity structure is equal to an integer multiple of half the wavelength of the blue light and half the wavelength of the red light; and / or, the quantum dot conversion layer includes green light quantum dots, which are used to convert the blue light into green light, and the cavity length of the microcavity structure is designed to be equal to an integer multiple of half the wavelength of the blue light and half the wavelength of the green light.

[0013] In one of the embodiments, the color-changing structure of the microcavity-enhanced quantum dots includes a black glue filling layer, and the black glue filling layer is coated on the side of the color-changing structure of the microcavity-enhanced quantum dots.

[0014] Second aspect

[0015] The present invention discloses an application of a microcavity enhanced quantum dot color-changing structure, and applies the microcavity enhanced quantum dot color-changing structure described in any of the foregoing embodiments to a Mini-LED / Micro-LED full-color display device.

[0016] The third aspect

[0017] The present invention discloses a method for preparing a color-changing structure of a microcavity-enhanced quantum dot, comprising the following steps:

[0018] Depositing a first reflective layer, preparing a substrate, and processing and stacking the first reflective layer on one side of the substrate;

[0019] Depositing a blue light-emitting layer, preparing the blue light-emitting layer and processing and stacking it on a side of the first reflective layer away from the substrate, wherein the blue light-emitting layer emits blue light;

[0020] Depositing a quantum dot conversion layer, processing and stacking a quantum dot conversion layer on the light-emitting side of the blue light-emitting layer, wherein the quantum dot conversion layer can convert the blue light into red light or green light;

[0021] Depositing a second reflective layer, and stacking the second reflective layer on a side of the quantum conversion layer away from the blue light-emitting layer;

[0022] A microcavity structure is formed between the first reflective layer and the second reflective layer, and the first reflective layer and the second reflective layer are configured to form a stable resonance condition of blue light and green light or a stable resonance condition of blue light and red light in the microcavity structure;

[0023] Wherein, the light is reflected in the microcavity structure to form a blue light standing wave and a red light standing wave, and along the extension direction of the cavity length of the microcavity structure, the blue light-emitting layer is located at the crest of the blue light standing wave, and the quantum dot conversion layer is located at the overlapping position of the crests of the red light standing wave and the blue light standing wave; or, the light is reflected in the microcavity structure to form a blue light standing wave and a green light standing wave, and along the extension direction of the cavity length of the microcavity structure, the blue light-emitting layer is located at the crest of the blue light standing wave; the quantum dot conversion layer is located at the overlapping position of the crests of the green light standing wave and the blue light standing wave.

[0024] In one of the embodiments, before the step of depositing the quantum dot conversion layer, a first isolation layer is processed and stacked on the light-emitting surface of the blue light-emitting layer, and the microcavity structure with different cavity lengths is obtained by spin coating the first isolation layer with different thicknesses; and / or, before the step of depositing the second reflective electrode, a second isolation layer is processed and stacked on the light-emitting surface of the quantum dot conversion layer, and the microcavity structure with different cavity lengths is obtained by spin coating the second isolation layer with different thicknesses.

[0025] In one embodiment, in the step of depositing the first reflective layer, an electron beam multiplication method is used to deposit multiple layers of high and low refractive index dielectric materials on one side of the substrate to form a DBR reflective layer as the first reflective layer; and / or, in the step of depositing the second reflective layer, an electron beam multiplication method is used to deposit multiple layers of high and low refractive index dielectric materials on the side of the quantum dot conversion layer away from the blue light-emitting layer to form a DBR reflective layer as the second reflective layer.

[0026] It can be seen from the above technical solutions that the embodiments of the present invention have at least the following advantages and positive effects:

[0027] The embodiment of the present invention provides a color conversion structure of microcavity enhanced quantum dots, wherein a microcavity structure is formed between a first reflective layer and a second reflective layer, and a high reflective area is formed, wherein stable blue light and red light resonance conditions are formed in the microcavity structure, and light is reflected in the microcavity structure to form a blue light standing wave and a red light standing wave, wherein in the extension direction of the cavity length of the microcavity structure, the blue light emitting layer is located at the crest position of the blue light standing wave, and the quantum dot conversion layer is located at the overlapping position of the crests of the red light standing wave and the blue light standing wave, and the blue light excitation material and the red and green quantum dots are both in the strongest light field area, thereby enhancing the excitation efficiency of the blue light and improving the luminous intensity of the red light; similarly, the luminous intensity of the green light can also be improved, thereby effectively improving the color conversion efficiency of the quantum dot conversion layer. This color conversion structure of microcavity enhanced quantum dots can be applied to Mini-LED / Micro-LED full-color display devices to improve the optical performance of full-color display devices.

[0028] On the other hand, the present application provides a method for preparing a color conversion structure of a microcavity-enhanced quantum dot. The design of the microcavity structure ensures the optimized distribution of the light field in the cavity, so that blue light and red and green light can be effectively enhanced and fed back in the same microcavity. Through reasonable cavity length and material selection, the microcavity structure can not only significantly improve the light conversion efficiency of quantum dots, but also reduce light leakage and light crosstalk, making the display effect purer and more stable. Compared with traditional display technology with fixed structures, the present application provides higher design flexibility and can be widely used in a variety of display needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0030] Figure 1 This is a schematic diagram of the overall structure of a microcavity-enhanced quantum dot color-conversion structure according to an embodiment of the present application;

[0031] Figure 2 The schematic diagram of the color conversion structure for converting blue light into red light;

[0032] Figure 3 Schematic diagram of the distribution of blue light standing waves and red light standing waves in a microcavity structure for converting blue light into red light;

[0033] Figure 4 This is a schematic diagram of a color conversion structure for converting blue light into green light;

[0034] Figure 5 Schematic diagram of standing wave mode distribution of light of different colors in the microcavity structure;

[0035] Figure 6 In this application, TiO 2 / SiO 2 Spectrum diagram in the microcavity structure formed by the DBR reflective layer;

[0036] Figure 7 This is a flow chart for the preparation of the transcolor structure.

[0037] The following are the descriptions of the reference numerals:

[0038] 10. Color transfer structure; 100. Substrate; 101. Microcavity structure; 200. First reflective layer; 300. Blue light-emitting layer; 310. n-electrode; 320. n-GaN; 330. Blue light multi-quantum well layer; 340. p-GaN; 350. p-electrode; 400. Quantum dot conversion layer; 410. Red light quantum dots; 420. Green light quantum dots; 500. Second reflective layer; 205. DBR reflective layer; 600. Isolation layer; 610. First isolation layer; 620. Second isolation layer; 700. Vinyl filling layer. DETAILED DESCRIPTION

[0039] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially used for illustration purposes rather than for limiting the present invention.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0041] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "setting", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] refer to Figure 1 The present application provides a microcavity enhanced quantum dot color conversion structure 10 (hereinafter referred to as: color conversion structure 10), which is a hierarchical structure state including a substrate 100, a first reflective layer 200, a blue light-emitting layer 300, a quantum dot conversion layer 400 and a second reflective layer 500 stacked in sequence, the blue light-emitting layer 300 emits blue light, and the quantum dot conversion layer 400, as a color conversion layer, can convert blue light into red light or green light. A microcavity structure 101 is formed between the first reflective layer 200 and the second reflective layer 500, and the vertical distance between the first reflective layer 200 and the second reflective layer 500 along the thickness direction of the hierarchical structure is the cavity length of the microcavity structure 101.

[0043] Combined with reference Figure 2 and Figure 3 In one embodiment, the quantum dot conversion layer 400 includes red light quantum dots 410, which are used to convert blue light into red light. The first reflective layer 200 and the second reflective layer 500 are configured to form stable resonance conditions of blue light and red light in the microcavity structure 101. Figure 3 It is shown that the light forms a blue light standing wave and a red light standing wave in the microcavity structure 101, and the crest of the blue light standing wave and the crest of the red light standing wave can overlap at a specific position of the microcavity structure. In the direction of the cavity length extension of the microcavity structure 101, the blue light-emitting layer 300 is located at the crest of the blue light standing wave, and the light field intensity at this position is maximized, ensuring the luminous efficiency and excitation intensity of the blue light. The quantum dot conversion layer 400 can convert blue light into red light, and the quantum dot conversion layer 400 with red light quantum dots 410 is located at the position where the crests of the blue light standing wave and the red light standing wave overlap. Through the standing wave superposition of the blue light and red light wavelengths at this position, the red light quantum dots 410 can absorb more blue light, thereby achieving more efficient light conversion and improving the color conversion rate of the red light quantum dots 410.

[0044] refer to Figure 4In one embodiment, the quantum dot conversion layer 400 includes green light quantum dots 420, which are used to convert blue light into green light. The first reflective layer 200 and the second reflective layer 500 are configured to form stable resonance conditions of blue light and green light in the microcavity structure 101. The light forms a blue light standing wave and a green light standing wave in the microcavity structure 101. The crest of the blue light standing wave and the crest of the red light standing wave can overlap at a specific position of the microcavity structure. In the direction of the cavity length extension of the microcavity structure 101, the blue light emitting layer 300 is located at the crest position of the blue light standing wave, and the light field intensity at this position is maximized, ensuring the luminous efficiency and excitation intensity of the blue light. The quantum dot conversion layer 400 can convert blue light into green light. The quantum dot conversion layer 400 with the green light quantum dots 420 is located at the position where the peaks of the blue light standing wave and the green light standing wave overlap. Through the superposition of the standing waves of the blue light and red light wavelengths at this position, the red light quantum dots 410 can absorb more blue light, thereby achieving more efficient light conversion and improving the color conversion rate of the green light quantum dots.

[0045] In one embodiment, the first reflective layer 200 and the second reflective layer 500 are configured to simultaneously form stable blue light and red light, and stable blue light and green light resonance conditions in the microcavity structure 101, and the light forms a blue light standing wave, a red light standing wave, and a green light standing wave in the microcavity structure 101, and the crest of the blue light standing wave can overlap with the crest of the red light standing wave or the crest of the green light standing wave at a specific position in the same microcavity structure 101. In the direction of extension of the cavity length of the microcavity structure 101, the blue light-emitting layer 300 is located at the crest of the blue light standing wave, and the quantum dot conversion layer 400 can be located at the position where the crest of the blue light standing wave overlaps with the crest of the red light standing wave, or at the position where the crest of the blue light standing wave overlaps with the crest of the green light standing wave according to the conversion color requirements. That is, the same color conversion structure 10 can realize two color conversion functions of blue light to red light and blue light to green light.

[0046] It should be noted that, for a structure that does not require color change, that is, only needs to emit blue light, it is only necessary to form a stable blue light standing wave in the microcavity structure 101 and place the blue light-emitting layer 300 at the peak position of the blue light standing wave to enhance the excitation efficiency of the blue light and improve the light efficiency and light intensity.

[0047] Preferably, in one embodiment, in the blue-to-red light conversion structure 10, the conditions for forming stable resonances of blue light and red light can be met, and the cavity length of the microcavity structure 101 is simultaneously equal to an integer multiple of a half wavelength of blue light and a half wavelength of red light, as shown in formula (1).

[0048] L=1 / 2.n.λ B =1 / 2.m.λ R (1)

[0049] Wherein, L is the cavity length of the microcavity structure 101; n and m are both positive integers; λB is the wavelength of blue light; R is the wavelength of red light; the unit of each parameter is nm. In one embodiment, the wavelength of blue light is 400nm, the wavelength of red light is 600nm, and the cavity length L of the microcavity structure 101 is designed to be an integer multiple of 600nm (the least common multiple of half wavelength of blue light and half wavelength of red light), so that stable resonance conditions of blue light and red light can be formed in the microcavity structure 101.

[0050] Preferably, in one embodiment, in the blue-to-green light conversion structure 10, the conditions for forming stable resonances of blue and green light can be met, and the cavity length of the microcavity structure 101 is simultaneously equal to an integer multiple of a half wavelength of blue light and a half wavelength of green light, as shown in formula (2).

[0051] L=1 / 2.n.λ B =1 / 2.m.λ G (2)

[0052] Wherein, L is the cavity length of the microcavity structure 101; n and m are both positive integers; λ B is the wavelength of blue light; G is the wavelength of green light; the unit of each parameter is nm.

[0053] Preferably, in one embodiment, in the color conversion structure 10 that satisfies both blue light conversion to red light and blue light conversion to green light, the cavity length of the microcavity structure 101 is simultaneously equal to an integer multiple of half the wavelength of blue light, half the wavelength of red light and half the wavelength of green light, as shown in formula (3).

[0054] L=1 / 2.n.λ B =1 / 2.m.λ R =1 / 2.i.λ G (3)

[0055] Wherein, L is the cavity length of the microcavity structure 101; n, m, i are all positive integers; λ B is the wavelength of blue light; R is the wavelength of red light; G is the wavelength of green light; the unit of each parameter is nm, and the cavity length L of the microcavity structure 101 is equal to the minimum integer multiple of the half wavelength of blue light and the half wavelength of green light.

[0056] refer to Figure 5The cavity length L of the microcavity structure 101 is set to an integer multiple of the half wavelength of different lights, which can ensure that lights of different color wavelengths form a stable standing wave distribution in the microcavity structure 101. Placing the luminescent material layer at the peak position of the corresponding standing wave, that is, the position where the light field is the strongest, can improve the light efficiency. It should be noted that the cavity length of the microcavity structure 101 is not limited to an integer multiple of the half wavelength of the light wave. As long as the realization principle formula that ensures that lights of different color wavelengths form a stable standing wave distribution in the microcavity structure 101 should be within the protection scope of this application.

[0057] Preferably, reference Figure 1 In one embodiment, the color-changing structure 10 includes an isolation layer 600 (Spacer), and the isolation layer 600 includes a first isolation layer 610, and the first isolation layer 610 is stacked and disposed between the quantum dot conversion layer 400 and the blue light-emitting layer 300 along the cavity length extension direction of the microcavity structure 101. The color-changing structure 10 includes a second isolation layer 620, and the second isolation layer 620 is stacked and disposed between the quantum dot conversion layer 400 and the second reflective layer 500 along the cavity length extension direction of the microcavity structure 101.

[0058] It should be noted that in the present application, the isolation layer 600 is used to protect the functional hierarchical structure in the color-changing structure 10 from damage during processing and deposition, or the functional layers are directly in contact with each other and corroded. The first isolation layer 610 is used to protect the blue light-emitting layer 300 from damage during the processing and deposition of the quantum dot conversion layer 400, and the second isolation layer 620 is used to protect the quantum dot conversion layer 400 from damage during the processing and deposition of the second electrode layer. On the other hand, the isolation layer 600 plays a necessary mechanical support function in the microcavity structure 101. Moreover, by adjusting the thickness of the isolation layer 600, the cavity length of the microcavity structure 101 can be changed to change the optical properties of the microcavity structure 101. Of course, in other embodiments, the cavity length of the microcavity structure 101 can also be changed by changing the thickness of other functional layers of the color-changing structure 10, but the process operation is more difficult to achieve. In addition, the material of the isolation layer 600 is selected from inorganic inert materials such as silicon dioxide, silicon nitride, aluminum oxide, and silicon carbide, which have good optical transparency, chemical stability, insulation, mechanical properties and other advantages. It is understandable that in the present application, the first isolation layer 610 or whether the first isolation layer 610 is provided or not is not limited. In the present application, as long as the microcavity structure 101 is achieved to enhance the color conversion rate of the quantum dot conversion layer 400, that is, a stable standing wave is formed in the microcavity structure 101, the blue light-emitting layer 300 is located at the crest of the blue light standing wave, and the quantum dot conversion layer 400 is located at the overlapping position of the crest of the blue light standing wave and the crest of the red and green standing waves.

[0059] Preferably, in one embodiment, in combination with reference Figure 1 and Figure 6The first reflection layer 200 and the second reflection layer 500 are both DBR reflection layers 205 (Bragg reflector). The microcavity structure 101 is formed of a high reflection area by the upper and lower DBR reflection layers 205 to ensure efficient light feedback. The DBR reflection layer 205 is made of a multilayer high and low refractive index TiO 2 / SiO 2 Stacked, TiO 2 The refractive index of SiO is 2.5. 2 The refractive index of the microcavity structure 101 is 1.45, and the refractive index inside the cavity is 1.8. Figure 6 As shown in the figure, the width of the high reflective area between the upper and lower DBR reflective layers 205 can reach 200nm, which can effectively reflect light and form a high-quality light field. Moreover, the DBR reflective layer 205 can stably form the resonance conditions of blue light and red and green light without considering the change of refractive index with wavelength. 2 / SiO 2 The distributed Bragg reflector (DBR) is used as a high reflection area, combined with a precisely adjusted cavity length meter, so that it can adapt to light sources of different wavelengths, especially the coexistence of blue light and red and green light. The high reflectivity of the DBR ensures multiple optical feedbacks in the microcavity structure 101, thereby achieving quantitative enhanced feedback for different wavelengths.

[0060] It should be noted that, in the present application, the first reflective layer 200 and the second reflective layer 500 are not necessarily DBR reflective layers 205. As long as the reflective layer can form a high reflection area and form a stable resonance condition of blue light and red and green light inside the microcavity structure 101 (such as a metal reflector, etc.), it should be protected. In addition, the material selection of the DBR reflective layer 205 is not limited to TiO 2 / SiO 2 Other high and low refractive index material layers such as Ta can also be selected 2 O 5 / SiO 2 , HfO 2 / SiO 2 wait.

[0061] Preferably, reference Figure 1In one embodiment, the blue light emitting layer 300 adopts a common blue light LED on the market, including an n-electrode 310, n-GaN 320, a blue light multi-quantum well layer 330, p-GaN 340, and a p-electrode 350 stacked in sequence, wherein the blue light multi-quantum well layer 330 emits blue light, and one of the n-electrode 310 and the p-electrode 350 is stacked on the first reflective layer 200, and the other is stacked on the quantum dot conversion layer 400. If a first isolation layer 610 is provided, the other is stacked on the first isolation layer 610. It should be noted that in the present application, the blue light emitting layer 300 does not necessarily adopt a blue light LED, and any hierarchical material structure that can emit blue light is within the protection scope of the present application.

[0062] Preferably, reference Figure 1 The color-changing structure 10 includes a black glue filling layer 700, which is coated on the side of the hierarchical structure of the color-changing structure 10, and the black glue filling layer 700 extends from the first reflective layer 200 to the second reflective layer 500, that is, the black glue filling layer 700 is arranged on the side of the microcavity structure 101. It should be noted that in the present application, whether the black glue filling layer 700 is arranged or not is not limited, and in other embodiments, other passivation layers and buffer layers can also be used to fill and coat the side of the microcavity structure 101.

[0063] On the second aspect, the present application provides an application of a microcavity-enhanced quantum dot color-changing structure 10, and applies the aforementioned color-changing structure 10 to a Mini-LED / Micro-LED full-color display device. Here, it is only necessary to arrange multiple blue light-emitting layers 300, a blue-to-green light color-changing structure 10, and a blue-to-red light color-changing structure 10 in a simple RGB array to combine them into a full-color display device. The design of the microcavity structure 101 in the color-changing structure 10 can not only significantly improve the color conversion rate of quantum dots and the performance of full-color devices, but also reduce light leakage and light crosstalk, making the display effect of the display device purer and more stable. The color-changing structure 10 can also be used to realize Resonant CavityLED devices or to realize LaserDiode devices.

[0064] Thirdly, combined with reference Figure 1 and Figure 7 The present application also provides a method for preparing a color-changing structure 10 of a microcavity-enhanced quantum dot, comprising the following steps:

[0065] S10, depositing a first reflective layer 200, preparing a substrate 100 as a substrate, and processing and stacking the first reflective layer 200 on one side of the substrate 100;

[0066] S20, depositing a blue light-emitting layer 300, preparing the blue light-emitting layer 300 and processing and stacking it on the side of the first reflective layer 200 away from the substrate 100, and the blue light-emitting layer 300 emits blue light;

[0067] S30, depositing a quantum dot conversion layer 400, processing and stacking the quantum dot conversion layer 400 on the light-emitting side of the blue light-emitting layer 300, wherein the quantum dot conversion layer 400 can convert blue light into red light or green light;

[0068] S40, depositing a second reflective layer 500, and processing and stacking the second reflective layer 500 on a side of the quantum dot conversion layer 400 away from the blue light-emitting layer 300;

[0069] A microcavity structure 101 is formed between the first reflective layer 200 and the second reflective layer 500, and the first reflective layer 200 and the second reflective layer 500 are configured to form a stable resonance condition of blue light and green light in the microcavity structure 101, or to form a stable resonance condition of blue light and red light. Wherein, the light forms a blue light standing wave and a red light standing wave in the microcavity structure 101, and along the extension direction of the cavity length of the microcavity structure 101, the blue light-emitting layer 300 is designed to be located at the crest position of the blue light standing wave, and the quantum dot conversion layer 400 is designed to be located at the overlapping position of the crest of the red light standing wave and the blue light standing wave. Alternatively, the light forms a blue light standing wave and a green light standing wave in the microcavity structure 101, and along the extension direction of the cavity length of the microcavity structure 101, the blue light-emitting layer 300 is designed to be located at the crest position of the blue light standing wave, and the quantum dot conversion layer 400 is designed to be located at the overlapping position of the crest of the green light standing wave and the blue light standing wave.

[0070] Preferably, in one embodiment, before the step of depositing the quantum dot conversion layer 400, the first isolation layer 610 is processed and stacked on the light-emitting surface of the blue light-emitting layer 300, and the microcavity structure 101 with different cavity lengths is obtained by spin-coating the first isolation layer 610 with different thicknesses, so as to adjust the optical performance of the microcavity structure 101. Of course, the first isolation layer 610 can also protect the quantum dot conversion layer 400 from direct contact with the light-emitting surface of the blue light-emitting layer 300 during the processing process, thereby causing damage to the corresponding contact functional layer, and play a protective function for the blue light-emitting layer 300 and the quantum dot conversion layer 400. Similarly, before the step of depositing the second reflective layer 500, the second isolation layer 620 can be processed and stacked on the light-emitting surface of the quantum dot conversion layer 400, and the microcavity structure 101 with different cavity lengths is obtained by spin-coating the second isolation layer 620 with different thicknesses, so as to adjust the optical performance of the microcavity structure 101. The second isolation layer 620 can also protect the second reflective layer 500 from direct contact with the light emitting surface of the quantum dot conversion layer 400 during processing, thereby avoiding damage to the corresponding contact functional layer, thereby playing a protective function for the quantum dot conversion layer 400 and the second reflective layer 500.

[0071] Preferably, in one embodiment, in the step of depositing the first reflective layer 200, multiple layers of high and low refractive index dielectric materials are deposited on one side of the substrate 100 by electron beam multiplication method to form a DBR reflective layer 205 as the first reflective layer 200. In the step of depositing the second reflective layer 500, multiple layers of high and low refractive index dielectric materials are deposited on the side of the quantum dot conversion layer 400 away from the blue light-emitting layer 300, or on the side of the second isolation layer away from the quantum dot conversion layer 400 by electron beam multiplication method to form a DBR reflective layer 205 as the first reflective layer 200. The high and low refractive index dielectric materials here include but are not limited to TiO 2 / SiO 2， Ta 2 O 5 / SiO 2 , HfO 2 / SiO 2 .

[0072] It should be noted that the present application uses the vernier effect, that is, by accurately positioning the peak of the light field and the peak of the standing wave, to place the blue light-emitting layer 300 at the peak position of the blue light standing wave, and at the same time find the peak of another blue light standing wave so that it coincides with the peak position of the red and green light standing wave. The quantum dot conversion layer 400 (red light quantum dots 410 or green light quantum dots 420) is placed at this overlapping position. Through this design, the blue light-emitting layer 300 (blue light-emitting material) and the quantum dot conversion layer 400 (red and green light-emitting material) are both in the area with the strongest light field, which enhances the excitation efficiency of the blue light, and also increases the luminous intensity of the red and green light, thereby effectively improving the color conversion rate of the quantum dot conversion layer 400.

[0073] The present invention provides a color conversion structure 10 of microcavity enhanced quantum dots, wherein a microcavity structure 101 is formed between a first reflective layer 200 and a second reflective layer 500, and a high reflection area is formed, wherein stable blue light and red light resonance conditions are formed in the microcavity structure 101, and light is reflected in the microcavity structure 101 to form a blue light standing wave and a red light standing wave. In the cavity length extension direction of the microcavity structure 101, the blue light emitting layer 300 is located at the crest position of the blue light standing wave, and the quantum dot conversion layer 400 is located at the overlapping position of the crest of the red light standing wave and the blue light standing wave. The blue light excitation material and the red and green quantum dots are both in the strongest light field area, thereby enhancing the excitation efficiency of the blue light and improving the luminous intensity of the red light; similarly, the luminous intensity of the green light can also be improved, thereby effectively improving the color conversion efficiency of the quantum dot conversion layer 400. This color conversion structure 10 of microcavity enhanced quantum dots can be applied to Mini-LED / Micro-LED full-color display devices to improve the optical performance of the full-color display devices.

[0074] On the other hand, the present application provides a method for preparing a color conversion structure 10 of a microcavity-enhanced quantum dot. The design of the microcavity structure 101 ensures the optimized distribution of the light field in the cavity, so that blue light and red and green light can be effectively enhanced and fed back in the same microcavity. Through reasonable cavity length and material selection, the microcavity structure 101 can not only significantly improve the light conversion efficiency of quantum dots, but also reduce light leakage and light crosstalk, making the display effect purer and more stable. Compared with traditional display technology with fixed structures, the present application provides higher design flexibility and can be widely used in a variety of display needs.

[0075] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A microcavity enhanced quantum dot color-changing structure, characterized in that: The invention comprises a substrate, a first reflective layer, a blue light-emitting layer, a quantum dot conversion layer and a second reflective layer which are sequentially stacked, wherein the blue light-emitting layer emits blue light, the quantum dot conversion layer can convert the blue light into red light or green light, a microcavity structure is formed between the first reflective layer and the second reflective layer, and the first reflective layer and the second reflective layer are configured to form a stable resonance condition of blue light and green light or a stable resonance condition of blue light and red light in the microcavity structure; Among them, the light is reflected in the microcavity structure to form a blue light standing wave and a red light standing wave, and along the extension direction of the cavity length of the microcavity structure, the blue light-emitting layer is located at the crest of the blue light standing wave; the quantum dot conversion layer is located at the overlapping position of the crests of the red light standing wave and the blue light standing wave; or, the light is reflected in the microcavity structure to form a blue light standing wave and a green light standing wave, and along the extension direction of the cavity length of the microcavity structure, the blue light-emitting layer is located at the crest of the blue light standing wave; the quantum dot conversion layer is located at the overlapping position of the crests of the green light standing wave and the blue light standing wave.

2. The color-changing structure of microcavity-enhanced quantum dots according to claim 1, characterized in that: The microcavity enhanced quantum dot color conversion structure comprises a first isolation layer, which is stacked and arranged between the quantum dot conversion layer and the blue light-emitting layer along the cavity length extension direction of the microcavity structure; and / or, The microcavity enhanced quantum dot color conversion structure comprises a second isolation layer, and the second isolation layer is stacked and arranged between the quantum dot conversion layer and the second reflective layer along the cavity length extension direction of the microcavity structure.

3. The color-changing structure of microcavity-enhanced quantum dots according to claim 1, characterized in that: The first reflection layer and the second reflection layer are both DBR reflection layers.

4. The color-changing structure of microcavity-enhanced quantum dots according to claim 1, characterized in that: The blue light-emitting layer includes an n-electrode, n-GaN, a blue light multi-quantum well layer, p-GaN, and a p-electrode stacked in sequence, and the blue light multi-quantum well emits the blue light; the n-electrode stack is arranged on the first reflective layer, and the p-electrode stack is arranged on the quantum dot conversion layer.

5. The color-changing structure of microcavity-enhanced quantum dots according to claim 1, characterized in that: The quantum dot conversion layer includes red light quantum dots, which are used to convert blue light into red light, and the cavity length of the microcavity structure is simultaneously equal to an integer multiple of half the wavelength of the blue light and half the wavelength of the red light; and / or, the quantum dot conversion layer includes green light quantum dots, which are used to convert the blue light into green light, and the cavity length of the microcavity structure is designed to be simultaneously equal to an integer multiple of half the wavelength of the blue light and half the wavelength of the green light.

6. The color-changing structure of microcavity-enhanced quantum dots according to claim 1, characterized in that: The color-changing structure of the microcavity-enhanced quantum dot comprises a black glue filling layer, and the black glue filling layer is coated on the side of the color-changing structure of the microcavity-enhanced quantum dot.

7. An application of a microcavity enhanced quantum dot color-changing structure, characterized in that: The color-changing structure of the microcavity-enhanced quantum dots described in claims 1 to 6 is applied to Mini-LED / Micro-LED full-color display devices.

8. A method for preparing a color-changing structure of a microcavity-enhanced quantum dot, characterized in that: The steps include: Depositing a first reflective layer, preparing a substrate, and processing and stacking the first reflective layer on one side of the substrate; Depositing a blue light-emitting layer, preparing the blue light-emitting layer and processing and stacking it on a side of the first reflective layer away from the substrate, wherein the blue light-emitting layer emits blue light; Depositing a quantum dot conversion layer, processing and stacking a quantum dot conversion layer on the light-emitting side of the blue light-emitting layer, wherein the quantum dot conversion layer can convert the blue light into red light or green light; Depositing a second reflective layer, and stacking the second reflective layer on a side of the quantum conversion layer away from the blue light-emitting layer; A microcavity structure is formed between the first reflective layer and the second reflective layer, and the first reflective layer and the second reflective layer are configured to form a stable resonance condition of blue light and green light or a stable resonance condition of blue light and red light in the microcavity structure; Wherein, the light is reflected in the microcavity structure to form a blue light standing wave and a red light standing wave, and along the extension direction of the cavity length of the microcavity structure, the blue light-emitting layer is located at the crest of the blue light standing wave, and the quantum dot conversion layer is located at the overlapping position of the crests of the red light standing wave and the blue light standing wave; or, the light is reflected in the microcavity structure to form a blue light standing wave and a green light standing wave, and along the extension direction of the cavity length of the microcavity structure, the blue light-emitting layer is located at the crest of the blue light standing wave; the quantum dot conversion layer is located at the overlapping position of the crests of the green light standing wave and the blue light standing wave.

9. The method for preparing the color-changing structure of microcavity-enhanced quantum dots according to claim 8, characterized in that: Before the step of depositing the quantum dot conversion layer, a first isolation layer is processed and stacked on the light-emitting surface of the blue light-emitting layer, and the microcavity structure with different cavity lengths is obtained by spin coating the first isolation layer with different thicknesses; and / or, before the step of depositing the second reflective electrode, a second isolation layer is processed and stacked on the light-emitting surface of the quantum dot conversion layer, and the microcavity structure with different cavity lengths is obtained by spin coating the second isolation layer with different thicknesses.

10. The method for preparing the color-changing structure of microcavity-enhanced quantum dots according to claim 8, characterized in that: In the step of depositing the first reflective layer, multiple layers of high and low refractive index dielectric materials are deposited on one side of the substrate using an electron beam multiplication method to form a DBR reflective layer as the first reflective layer; and / or, in the step of depositing the second reflective layer, multiple layers of high and low refractive index dielectric materials are deposited on the side of the quantum dot conversion layer away from the blue light-emitting layer using an electron beam multiplication method to form a DBR reflective layer as the second reflective layer.

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